During the Holiday season, or even for birthdays and other celebrations, surprises of all sizes tend to take place. In the case of a special event or holiday, surprises are typically a good thing. Now, there are two sides to surprises: the person who does the surprising, and the person who gets surprised.
The person who does the surprising.
This person who is doing the surprising needs to keep it a complete secret. If they were to mention anything about a surprise to the person receiving it, then that person will more than likely start to ask a bunch of questions because they are now in suspense and "can't wait" to see what it could be. The best way to keep a secret, is to keep it to yourself (unless for some reason there isn't a way you can succeed with the surprise on your own). Don't bother mentioning a single thing, because if you do the person who is supposed to be surprised will not be as surprised as they would be if you would not have told them.
The person who is being surprised.
Everyone acts differently whenever they get a surprise. There is always that one person who overreacts to please the person who gave them the gift. Their voice will get high and squeaky and it is completely obvious that they are trying to please the other person. Then there is that person who has no emotions and makes the other person think they are not thankful or don't like what they got them. This is simple really; that person simply does not know how to react or what to say in such a situation. These are usually the people who are bad at keeping conversations going and are socially awkward according to society. But, no matter which one of these you are, just be sure to say thank you to whomever gave you the special surprise.